A longitudinal study in a large corporation will be conducted to obtain the prevalence and incidence of drug use. Information will be collected on risk factors influencing drug use and the relationship of job performance and productivity of employees to their use of drugs. The study will examine changes in drug use over a one year period and make recommendations for setting up model drug screening programs involving labor-management cooperation and guidelines for prevention programs at worksites. The study, in addition to making up for deficiencies in our knowledge about drug use at worksites will identify which risk factors would, in the future be appropriate for intervention, thus reducing drug problems in industry and improving the health of workers and the community. The study will be conducted using 4,000 employees at a Michigan site. 3,000 will be randomly selected for the treatment and 1,000 for the control condition. The treatment group will have their personnel records abstracted, urine sample analyzed (Abuscreen and GC/MS confirmations) and be interviewed by telephone on risk factors, job related variables and drug use. All 4,000 subjects will be followed-up a year later by record abstraction and a short telephone interview related to drug use. Cross-sectional and longitudinal statistical comparisons will be made between employees. A major emphasis of the study will be an outreach program to ensure participation, consisting of group meetings at the plant and a telephone information service to provide employees with details, first about the study and second, on drug use information. A committee composed of union, management and the research team will be formed to advise the research team and perform liaison functions with their constituents.